Autonomic nervous system (ANS) activity and attention has been assessed in boys with diagnoses in the Disruptive Behavior Disorder (DBD)spectrum (Conduct Disorder, Oppositional Defiant Disorder and/or Attention Deficit Hyperactivity Disorder [ADHD]), selected for their antisocial and disruptive behavior, in children and adolescents with Obsessive Compulsive Disorder (OCD), some with co-diagnoses of ADHD and Tourettes Syndrome and in normal control children and adolescents. We recorded skin conductance (SC) and heart rate (HR) during a rest period, a series of nonsignal tones, and a simple reaction time (RT) task. Attention was assessed by two RT tasks which have been used extensively in schizophrenia research: 1) Simple RT with constant and variable preparatory intervals, and 2) Simple, choice, and "crossmodal" RT to lights and tones. A major purpose of these projects is to look for ANS and attentional markers of diagnosis and subdiagnosis and to determine how these processes might be related to symptoms. In the case of the DBD subjects an objective was to determine if the data support the concept that the subdiagnostic groups can be considered part of a spectrum of similar disorders. In general, the data showed many common differences between the subdiagnostic groups and normal controls and thus support the concept of the DBD spectrum. We are studying the relationships between metabolites of serotonin. norepinephrine, and dopamine measured from cerebrospinal fluid and ANS responsivity in the patient groups. A 2- year clinical followup of the DBD subjects has been completed and some evidence that low ANS activity predicts poor outcome was found. The ANS and attention test are being repeated on a new sample of younger boys with ADHD. Exploratory tests of children with elective mutism are being carried out.